Don't put off brake fluid changes

[flybobbie]

Scary experience last week, around a blind bend a post van pulled out.
So applied brakes and shocked how slow and how far pedal traveled.
First half of pedal movement did virtually nothing.
First time used in anger for a long time.

So today changed the fluid all well now.
Touch pedal and it wants to throw you through windshield.

But then realised it's been 6 years since i last changed it.
How time passes.
Picture shows left fluid from the front brake lines and right the rear fluid, which already is watered down with new flushed fluid.
So car pretty much felt like rear brakes were not doing much.

Interesting front left bleed nipple, can you see the fault?

 

[Z4Mariner]

We would have to see the back side to be sure, but I'll wager that the back side looks like the side you show us, and you got the "added value" version with a little extra metal on the sealing end of that screw ?

Z4Mariner

 

[buzyg]

Is it not a minimum bi annual service item on all Zeds?

Regardless, glad you got away with it and now have a safer car.

 

[SonnyA85]

Is it not a minimum bi annual service item on all Zeds?

Regardless, glad you got away with it and now have a safer car.

Brake fluid absorbs water. Over time it gets worse and worse. The more water the lower the boiling point.

This is usually what causes calipers to seize as water causes corrosion and overheating to the point of failure.

It should be changed at bare minimum once every 2 years. If you drive hard then yearly.

 

[Zed Baron]

I always get a brake fluid change done at the same time as the engine oil.

 

[flybobbie]

I always get a brake fluid change done at the same time as the engine oil.

Good idea, it doesn't take too much effort diy for the knowledge you have effective braking.
Have been ignoring the dash reminder, i guess all other cars i have owned only ever changed the fluid once, then got rid of car before the next was due.

 

[flybobbie]

We would have to see the back side to be sure, but I'll wager that the back side looks like the side you show us, and you got the "added value" version with a little extra metal on the sealing end of that screw ?

Z4Mariner

Solid all through.
Threw me the first time i tried to bleed, like what the eck!

 

[Zulu4]

We would have to see the back side to be sure, but I'll wager that the back side looks like the side you show us, and you got the "added value" version with a little extra metal on the sealing end of that screw ?

Z4Mariner

Solid all through.
Threw me the first time i tried to bleed, like what the eck!

:? I wonder why they even bothered to put a nipple on the top, if it is only being used as a plug.

 

[flybobbie]

I think it's just one of thousands that snook through the machine shop.
But why didn't BMW have a problem with it at the factory?

 

[wanderer]

Screwfix sells a nice brake fluid tester under€10.

I think I've tried numerous devices over the years for Brake bleeding.
I picked this up last week before doing the Saab brakes. It works a treat. For £6.50 one cannot go wrong.
https://www.halfords.com/motoring/engine-oils-and-fluids/brake-clutch-fluid/europat-vizibleed-bleed-aid-321117.html

 

[mike1]

I think the nipple at the end is for a hose. I use a Motive pressure bleeder with bottles that have hoses on them. I put a box wrench on the bleeder, then attach the hose and open the bleeder. I also have bottles marked so I know how much is being replaced. Works good.

 

[Special Kay]

Great reminder OP, it's been a few years since I last changed my brake fluid on the daily workhorse. Looks like I'll be refreshing mine very soon.

 

[flybobbie]

Screwfix sells a nice brake fluid tester under€10.

I think I've tried numerous devices over the years for Brake bleeding.
I picked this up last week before doing the Saab brakes. It works a treat. For £6.50 one cannot go wrong.
https://www.halfords.com/motoring/engine-oils-and-fluids/brake-clutch-fluid/europat-vizibleed-bleed-aid-321117.html

Length of clear hose about £2 a metre, jam jar, 11mm ring spanner, did the job.

 

[wanderer]

Screwfix sells a nice brake fluid tester under€10.

I think I've tried numerous devices over the years for Brake bleeding.
I picked this up last week before doing the Saab brakes. It works a treat. For £6.50 one cannot go wrong.
https://www.halfords.com/motoring/engine-oils-and-fluids/brake-clutch-fluid/europat-vizibleed-bleed-aid-321117.html

Length of clear hose about £2 a metre, jam jar, 11mm ring spanner, did the job.

Have all that.
This allows you to Bleed the brakes as a one man job.
Pump the brakes, the valve mechanism at the end prevents return of fluid and air into the system.
No need for one person to be pumping and the other to release & tighten while telling the other to pump & hold.

I tried a Sealy vacuum system but the cap wasn't a good fit for reservoir tank so ended up with fluid being pushed out of the side of the cap.

This is simples and cheap as chips. A no brainer.

 

[Special Kay]

Managed to change mine yesterday. Thankfully, my fluid was nowhere near as dirty as the OP's, but dirty enough to warrant a change. So glad I got it done. Thanks for the reminder OP

 

[grannyknot]

I don't have any willing helpers so I install Speed Bleeders on all my cars, makes flushing the system much easier. The sealant on the threads keeps the air from sneaking around.

 

[flybobbie]

So my soft brake problem has come back.
Pedal moves a long way down before any useful brake force becomes active.
Not lost any brake fluid.
Turn engine off and pump brake get about 3 strokes and vacuum all gone, that seems normal.
But then apply force and pedal slowly moves down, with enough force seems to bottom out.
It's like the master seals have gone, or at least say the rear.
I wonder if the black stuff in the fluid was the rear brake master cylinder seals rotted.
I did use DOT 5.1, but not recommended for the Z i recently find out.

From past experience i think i need to replace the master cylinder.

 

[enuff_zed]

So my soft brake problem has come back.
Pedal moves a long way down before any useful brake force becomes active.
Not lost any brake fluid.
Turn engine off and pump brake get about 3 strokes and vacuum all gone, that seems normal.
But then apply force and pedal slowly moves down, with enough force seems to bottom out.
It's like the master seals have gone, or at least say the rear.
I wonder if the black stuff in the fluid was the rear brake master cylinder seals rotted.
I did use DOT 5.1, but not recommended for the Z i recently find out.

From past experience i think i need to replace the master cylinder.

Had the same issue on old Capris. The internal seals in the master cylinder fail (often due to manual pumping of the pedal during bleeding, which runs them past their normal range of travel). Then the fluid simply moves from one side of the piston to the other.

 

[flybobbie]

Same on TR7, every year changing seals, new cylinder was too expensive at the time.

Well checking prices for E85's cylinders they cost £25.
Price for Z4 E89 £300 upwards, what a surprise.

So just bought 2nd hand cylinder complete with servo from breakers, £40.
I will try that cheap enough to replace the lot, or choose best bits.

Just ran the abs bleed through again no difference. But you can hear what sounds like fluid going past the seal as you push the lever down.

 

[flybobbie]

Well all sorted.
Just fitted the secondhand master cylinder.
So there must have been something wrong with the original.